Automatic turn-off switch and load-limit device



July 27 1926. 1,594,096

1.. s. FOLTZ AUTOMATIC TURN-OFF swn'cn AND LOAD mun- DEVICE Filed June 22. 1921 2 sheds-sheet 1 INVENTOR L. :5. F0162,

'4 TTORNEYS WITNESSES July 27 1926. 1,594,096

' L. s. FOLTZ AUTOMATIC TURN-OFF SW] ITC H AND LOAD LIMIT DEVICE Filed June 22. 1921 2 Sheets-Sheet 2 WI TNESSES INVENTOR L Foltz,

A TTORNE Y8 Patented July 27, 1926.

LEROY STEWART FOLTZ, OF EAST LANSING, MICHIGAN.

AUTOMATIC TURN-OFF SWITCH AND LOAD-LIMIT DEVICE.

Application filed June 22, 1921. Serial No. 479,577.

This invention relates to automatic switches and load limit devices.

An important object of this invention is to provide a switch having novel means whereby the circuit through the same is antomatically broken at the end of an interval of time.

A further aim of the invention is to 1'0- vide a switch which may be used as a. oad limit for overcoming the danger of fire due to loading a circuit to a fuse capacity and then fusing more heavily.

Other objects and advantages will be apparent during the course of the following descri tion. In t e accompanying drawings formin a part of this application and in which like numerals are employed to designate like parts throughout the same Figure 1 is a vertical section through the switch.

Figure 2 is a vertical transverse section through the same.

Figure .3 is a horizontal section taken on line 33 of Figure 1.

Figure 4 is a pers ective of a cut oil plunger embodied in t e invention.

Figure 5 is a vertical section through a modified form of the invention.

Figure 6 is a vertical transverse section taken on line 66 of Figure 5.

Figure 7 is a horizontal section taken on line 77 of Figure 5.

In thedrawings, the numeral 10 designates a casing within which is arranged a air of switch blades 11 pivotally supported By means of a stationary pin 12 extended laterally from the upper portion of a partition 13. As illustrated in Figure 1 the switch blades 11 are tapered toward their lower ends and are adapted for electrical connection with contacts 15 carried by insulator blocks l6. Contacts 15 have electrical connection with circuit wires 17 which in turn extend through bushings 19 in the partition 13 and have connection with posts 20 secured in one side of the casing.

One of the wires 17 is connected to a heating element 21 preferably in the nature of a coil and supported by arms 22 of insulating material, said arms 22 being extended laterally from the partition. With reference to Figure 2 it will be observed that the part1- tion 13 defines a heating cell 24 and a switch cell 25.

In the operation of the improved switch,

heated. The thermostatic trigger 27 formed.

of thermostatic metal is curved longitudinally and detachably supports a yoke 28 inits elevated position so that the switch blades- 11 which are extended through the yoke will be held in engagement with the contacts 15. rises as the result of an increase in the temperature of the cell 24 the thermostatic trigger 27 moves in the direction of the part1- tion 13 and is thereby released from engagement with the yoke 28 so that the -coiled spring 30 mounted on a plunger 31 may draw the yoke downwardly for disengaging the switch blades 11 from the contacts 15. With the switch blades 11 thus withdrawn from contact with the members 15 the circuit is broken and cannot again be completed until the plunger or operating member 31 is manually elevated by means of en aging the knob 33 of the same with the ban and causing the same to move upwardly.

When the yoke 28 is released and moved to its lowermost position the thermostatic trigger 27 exerts a slight pressure on the same and when it is desired to reset the switch it is merely necessary to push u wardly on the knob 33 so that the end of tile thermostatic trigger will be engaged with the underside of the yoke 28.

Should it be desired to interrupt the circuit manually it is merely necessary to press inwardly on the knob 35 of a releasing plunger 36 extended through one side of the casing and having its end bifurcated to define a sides 0 the plunger31. As the arms 37 arranged on opposite sides of the plunger are disposed in the path of travel of the yoke 28 the said arms act as stop elements for limiting the downward movement of the yoke. Therefore, when it is desired to reset the switch, it is only necessary to push upwardly a slight distance on the knob 33 to reen age the yoke with the forward end of the t ermostatic bar.

In carrying out the invention the partition 13 may e formed with openings-40 or with heat conducting inserts to permit of the transmission of heat from the cell 24 to the cell 25 whereby the thermostatic bar may operate. However, the transmission of When the temperature in the cell 25 air of arms arranged on opposite llu heat from the cell 24 to the cell 25 is delayed so that the thermostatic bar 37 is not rendered unduly sensitive and will not break the circuit sooner than is desired.

In the modified form of the invention the casing 42 is formed with insulating blocks 43 having contacts 44 with which electric wires 45 are connected in the usual manner. The contact plates 44 are inclined downwardly and are arranged in the path of travel of the an ularly extended end portions 46 of a switch blade 47. The switch blade 47 has connection with a longitudinally movable plunger 48 extended out through the casing and provided with a knob 49 adapted to be engaged by the operator when it is desired to manually engage the angularly extended end portions of the blade 47 with the contacts 44. The switch blade 47 is held in its operative position by means of a thermostatic trigger 50 anchored at one end to a partition 51 or elsewhere as indicated at 52. It will be noted that the thermostatic trigger 50 extends at an angle to the plane of the partition 51 and is detachably engaged with a holding member 186 having connection with the switch blade so that when the cell 53 within which the trigger is arranged becomes heated, the thermostatic trigger is released to permit the blade to move out of contact with the members 44. A suitable spacing element 193 may be located between the blade 47 and the holding member 186.

The partition 51 defines the switch cell or chamber 53 and a heating cell 54 within which is arranged a heater 56 of any desired construction. The heater 56 of course, has connection with the electric wire and when the circuit is closed the heating element raises the temperature of the cell 54 and raises the temperature of the cell 53. By thus raising the temperature of the cell 53 the thermostatic trigger 50 is operated to permit a coiled spring 67 arranged on the plunger to move the blade 47 out of engagement with the contact 44.

The thermostatic trigger 50 may be manually operated by means of a turn off plunger 59 having a knob 60 extended exteriorly of the casing so that the same may be engaged by the operator with convenience. The forward end of the turn off plunger 59 is bifurcated to provide an opening which slidably receives the plunger 48 and to provide a pair of arms 61 arranged on opposite sides of the plunger and constituting a stop element for limiting the movement of the switch blade. 7

By specially designing the heating element and the resetting mechanisms the device may be used as a load limit and will reduce fire hazards to a minimum.

As illustrated in Figure 2 a shorting switch blade 62 may be provided for cutting out the heating element 21 and 56 and making the automatic feature inoperative.

In the practice of the invention a switch cell may be lined or partly lined with heat insulating material in order to secure slow timing.

Having thus described my invention, what is claimed is z- 1. A circuit closer comprising a casing, an intermediate partition in said casing dividing the same into a pair of cells, in one of which is located aheating member and in the other a set of contacts which may be opened by a thermostatic trigger, or operated manually.

QJA circuit closer comprising stationary and movable contacts, a yoke slidably engaged with and receiving said movable contact and having a plunger adapted to be manually engaged for positioning the movable contact, and a thermostatic trigger of elongated formation engaged with said yoke whereby to normally hold the movable contact in engagement with the stationary contact.

3. A circuit closer comprising pairs of stationary and movable contacts, a yoke having openings receiving said movable contacts, said movable contacts being pivotally supported and controlled by said yoke, and a thermostatic trigger of elongated formation engaged with said yoke whereby to normally hold the movable contacts in engagement with the stationary contacts.

4. A circuit closer comprising stationary and movable contacts, said movable contact being pivotally supported, a yoke having sliding engagement with the movable contact to form a means to control the movable contact, a trigger of elongated formation engaged with said yoke whereby to normally hold the movable contact in engagement with the stationary contact, and means whereby to manuall release said trigger from engagement with said yoke, said means being in the path of travel of said yoke and limiting the movement of the same.

5. A circuit closer comprising a pivotally supported contact, a yoke having sliding engagement with the contact, and forming a means to control the same, a thermostatic trigger normally holding said yoke in a set position, a manually controlled turn off member adapted for releasing said trigger and being in the path of travel of said yoke whereby to limit the movement of the same.

6. A switch comprising a casing, a thermostatic trigger of elongated formation arranged in said casing, a switch arranged in said casing and inclusive of stationary and movable contacts, a yoke receiving said movable contact and provided with an op erating member, and means associated with said oIpera-ting member for. drawing said movab e contact out of engagement with said same in set position, and means to manually release said thermostatic trigger from engagement with the yoke.

8. A circuit closer comprising a casing, a partitiontherein dividing the same into a pair of cells the said partition between the cells being of such material and formation as to regulate'to a desired degree the rate of passage of heat from the heating member to the thermostatic trigger.

9. A circuit closercomprising a longitudinal movable control member, a contact connected to and movable with said control member, a thermostatic trigger normally holding said 'contact in a set position, a spring for urging said control member to inoperative position upon being released anda manually controlled trigger releasing member straddling iting the movement of the same.

10. A circuit closer comprisin a casing, stationary contacts carried there y, a movable contact having engagement with stationary contacts, a longitudinal movable control member connected to said movable contact, a spring confined within one end of said casing and said movable contact for urging said control member to inoperative position, a trigger normally holding said movable contact in en agement with said stationary contacts, sai control member being provlded with a hand grip exteriorly of the casing, and a'releasing member for the trigger havin a knob arranged in frontlof the casing an forming a means whereby the releasing member may be operated for releasing the trigger, said releasing member being arranged in the path of travel of said movable contact and limiting themovement of the same.

LEROY STEWART FOLTZ.

said control member and'lim- 

